The present invention relates to an adaptor for collecting expiratory information capable of measuring carbon dioxide concentration from both nasal expiration gas and oral expiration gas of one subject, and of measuring airflow pressure of the nasal expiration gas.
The present invention also relates to a biological information processing system using such an adaptor.
In recent years, a steep condition has been particularly examined to check a driver's health in view of safety in various transportation facilities. That is, in many cases, an examination of a sleep apnea syndrome (SAS) is carried out. In order to examine the sleep apnea syndrome, respirations are detected by measuring airflow pressure together with various parameters through the use of a nasal cannula. Recently, in addition to the respiration detection, an activity of a respiratory center and an amount of carbon dioxide tension in a body have been examined by measuring carbon dioxide concentration in expiration.
As a technique for measuring the carbon dioxide concentration in expiration, Japanese Patent Publication No. 11-267223A teaches that nasal tubes inserted into nostrils are connected to a tube for collecting oral expiration gas at a connecting portion, and a side-stream type capnometer samples respiratory gas from the connecting portion. Further, Japanese Patent Publication No. 2004-321721A discloses a device configured such that nasal expiration gas and oral expiration gas are lead to a small-sized carbon dioxide sensor disposed right below nostrils.
However, in the above techniques, it is possible to measure carbon dioxide concentration of expiration, but it is not possible to measure airflow pressure at the same time. Additionally, in the disclosed devices, it is possible to measure carbon dioxide concentration of nasal expiration gas or oral expiration gas, but it is not possible to distinguish the nasal expiration gas and the oral expiration gas.
In addition, United States Published Application No. 2005/0284484 A1 discloses a device for measuring both airflow pressure and carbon dioxide. This device is configured such that a nasal cannula is divided into left and right spaces by a partition wall so as to measure carbon dioxide in one space and to measure airflow pressure in other space. However, in the device disclosed in this publication, since expiration is individually used while being extracted from each of left and right nostrils, information on only one nostril is obtained at the time one nostril is blocked, and thus there would be a case that satisfactory examination cannot be performed.
In addition to the above techniques, a tube for collecting nasal expiration gas and a tube for collecting carbon dioxide may be separately provided and both are inserted into the respective nostrils. However, particularly, in a case where a subject is a child, it is burdensome to insert two types of tubes into the nostrils.